Send me a message if you're interested in Technology or Science Workshops in Flanders, Brussels or the Southern of the Netherlands. I have over 15 years of experience in developing and giving creative workshops for children (and sometimes adults): rockets, mousetrap cars, solar powered vehicles, hovercrafts, RC blimps... Another hobby of mine is sculpting things, mainly dolls...

Hi Sonnyp99,Cool project!First, using a motor as generator is much simpler than build your own stator and rotor. Even commercial small charging devices (think crank torches, some of which can charge cell phones) are often based on an existing motor used as a generator. For a more high end applications it is very often a device specifically built with specs as a generator, but still with the same technology and on the same production lines as motors.Most low voltage motors, including stepper motors do keep working in clean sweet water for days, weeks and even longer.It does depend on the type of motor and it is hard to tell in advance.But most do last quite a while, so if you only need to explore and demonstrate a working principle you can omit any waterproofing.Dirty and in particular s...see more »Hi Sonnyp99,Cool project!First, using a motor as generator is much simpler than build your own stator and rotor. Even commercial small charging devices (think crank torches, some of which can charge cell phones) are often based on an existing motor used as a generator. For a more high end applications it is very often a device specifically built with specs as a generator, but still with the same technology and on the same production lines as motors.Most low voltage motors, including stepper motors do keep working in clean sweet water for days, weeks and even longer.It does depend on the type of motor and it is hard to tell in advance.But most do last quite a while, so if you only need to explore and demonstrate a working principle you can omit any waterproofing.Dirty and in particular salty water will probably shorten the motor's lifetime considerably.If however you want to demonstrate how a real reliable product could be made, you should waterproof your motor.An accessible approach is using waterproof prop shaft assemblies as sold for RC model boats.Succes,masynmachien